Many Benefits from Intracoronary Abxicimab in Diabetics

Benefits not seen in STEMI patients without diabetes

After ST-segment elevation MI (STEMI), a recent study found that abciximab (Reopro) was most effective when administered during primary percutaneous coronary intervention (PCI).

A meta-analysis found individuals with diabetes were less likely to experience stent thrombosis (1.3% versus 4.8%, HR 0.27, 95% CI 0.08 to 0.98), death (5.8% versus 11.2%, HR 0.51, 95% CI 0.26 to 0.98), and combined death or reinfarction (9.2% versus 17.6%, HR 0.49, 95% CI 0.28 to 0.83), after 1 year of receiving an intracoronary instead of intravenous bolus of the glycoprotein IIb/IIIa inhibitor, reported a study published in the Journal of the American College of Cardiology.

On cardiac MRI, this group also showed a greater increase in the myocardial salvage index after PCI (54.4 versus 39, P=0.011), according to authors Raffaele Piccolo, MD, of Bern University Hospital in Switzerland, and colleagues.

"In diabetic patients with STEMI, the administration of intracoronary abciximab improved the effectiveness of primary PCI compared with the intravenous bolus," they concluded.

"The identification of diabetic patients as potential candidates who can benefit to a greater extent from an intracoronary bolus of abciximab during primary PCI may have important implications because diabetes is present in approximately one-third of patients undergoing PCI and conveys a high residual risk after myocardial revascularization."

In an accompanying editorial, the pair honed in on the limitations of the study, asking: "Is a 51% reduction in mortality or reinfarction realistic for a study comparing two administration methods for the same drug?"

They pointed out that the superior platelet inhibition of intracoronary abciximab waned at 30 minutes after bolus injection. "It seems unrealistic that the substantial mortality benefit (most pronounced between 30 days and 1 year) and reduction in stent thrombosis observed ... is achieved in just these 30 min," Henriques and Kikkert wrote, suggesting that the results of the meta-analysis may have been due to chance.

Furthermore, "stent thrombosis rates were unusually low in the intracoronary abciximab group, considering that these patients were treated with bare-metal stents and clopidogrel [Plavix] in the majority of cases ... The current study remains grossly underpowered to detect true differences in mortality, let alone stent thrombosis."

Also contributing to the weaknesses of the meta-analysis were the lack of information on key variables such as type of therapy of diabetes and cause of death, Piccolo and colleagues acknowledged.

"We will need adequately powered trials randomizing patients with diabetes and STEMI to either intracoronary abciximab or placebo before we can adopt this treatment into clinical practice," the editorialists concluded.

There were three randomized studies included in the meta-analysis with a total of 2,470 participants, among whom 19% had diabetes.

Abciximab introduced through the intracoronary route was not linked to a reduction in death or reinfarction among non-diabetics, nor did this group show an advantage in myocardial salvage index between administration strategies.

The editorialists suggested that even if the straight-to-the-heart strategy really held an advantage, the case for abciximab may be a moot point.

"Over the past decade, refinements in interventional techniques and antiplatelet therapy have significantly reduced the risk of recurrent ischemic events and alleviated the need for platelet inhibition with glycoprotein IIb/IIIa inhibitors," according to Henriques and Kikkert. They cited two examples: drug-eluting stent technology that has reduced the risk of stent thrombosis and next-generation P2Y12 inhibitors -- prasugrel (Effient) and ticagrelor (Brilinta) -- that have lowered the odds of recurrent ischemic events.

"Given that treatment with glycoprotein IIb/IIIa inhibitors is associated with potential harm, the utility of glycoprotein IIb/IIIa inhibitors when added to current STEMI treatment is debatable. As a result, the routine use of glycoprotein IIb/IIIa inhibitors during primary PCI has significantly declined over the past decade," they noted.

Piccolo disclosed receiving a research grant from the Veronesi Foundation.

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